Lennox 29W64 2-Stage SPST Normally Opened 0.90/130" WC

The Lennox 29W64 is a 2-stage pressure switch that is used in the HVAC systems. It serves as a safety guard since it measures the pressure of air inside the system. When pressure levels rise to the set limits of 0.90/130" WC the switch gives on/off signals to your HVAC equipment. This ensures that pressure levels do not get too high which may damage the interior or components of the building. An SPST switch is used, it opens and closes a single circuit and is safer operating at low voltage, 24 VAC, hence the systems benefit from this.